Generally, Dual or Multi SIM (e.g., a first SIM and a second SIM) phones are desirable by users in growing economies as it allows the user to maintain several contexts and manage business with greater ease. Further, usage of Dual-SIM phones is expected to grow at a compound annual growth rate (CAGR) of +17% and Dual-SIM phones may play a key role during migration from Third Generation (3G) towards Fourth Generation (4G) Long Term Evolution (LTE). Further, DSDS devices currently dominate the dual-SIM market with over a 90% share in 2014; the remaining 10% is attributed to Dual-SIM Dual Active (DSDA) devices.
While handling a priority operation on the second SIM of a DSDS device, operation of a Radio Frequency (RF) resource is paused in the first SIM of the DSDS device to grant the RF resource to the second SIM. This mechanism of tuning the RF resource from the first SIM to the second SIM is called RF tune away. An RF resume mechanism is employed to resume operation again on the first SIM and the intervening period of inactivity in the first SIM is called ‘RF blackout’. The DSDS device may tune away the RF resource to attend to a high priority signaling procedure on the second SIM. For example, in a DSDS design, a Packet Switched (PS) data operation on the first SIM is considered a low priority whereas, signaling, paging, system information reading, and measurements on the second SIM are considered high priority operations. While handling a higher priority operation on the second SIM, operation of the RF resource is paused in the first SIM to grant the RF resource to the second SIM. Further, there are several other events which may come up based on different protocol and system improvement related scenarios under which operation of the RF resource may be paused in the first SIM to grant the RF resource to the second SIM.
In some systems and methods, during the RF blackout, the DSDS device does not respond to a scheduler in an eNodeB (eNB). However, the eNB may apply adaptation on a link which may cause mistrust in communication between a network entity and the DSDS device. As a protection, the scheduler applies more correction on a DSDS device's feedback, which impacts the resource allocation for the DSDS device. This scenario may cause resource wastage at the network entity and at the same time impact throughput at the DSDS device. Further, this scenario may lead to Radio Link Failure (RLF) and Radio Resource Control (RRC) re-establishment (RRE), causing a delay in resource allocation for the DSDS device.
The DSDS device encounters a delay in resource allocation post RF blackout, a degradation of throughput, an increase in power consumption, loss of service, paging misses, and scalability for N (number) SIM Standby. The network entity encounters resource wastage leading to degradation in system capacity, additional resource usage and contention handling post RF blackout, malfunctioning control mechanisms (such as link adaptation, power control, etc.), and throughput degradation. An operator encounters inferior and frequent RLF/RRE causing Key Performance Indicator (KPI) (such as call success rate and throughput) degradation, and loss of revenue. In some systems and methods, attempts are made to use an RRC signaling connection release indication specifically, the indication corresponds with a “PS resource suspension”, which suspends the allocation of resources. However, these systems and methods may suffer from delay caused by Radio Link Control (RLC).